1. Field of the Invention
The invention relates to position adjusting devices, and more particularly to adjusting devices for a seat, a couch or a bed.
2. Description of the Related Art
An adjusting device for beds is known by German Utility Model 88 06 094.2; EP 372 032. The aim being to construct such a device in a more compact form compared with previously known adjusting devices and to configure it in a simpler manner without cable laying and wiring work in order to facilitate the assembly. To this end, it is proposed to arranged known linear drives in a box-shaped housing, adjusting spindles with screwed-on adjusting nuts being mounted in guides of the housing and longitudinal and/or transverse adjusting ribs being provided in order to adjust the housing. In this case, the electric motor is connected via worm gearing to the screw spindle with adjusting nuts, and the nuts bears against an independent bell-crank lever, the arm lengths of which help to determine the length and the height of the housing. The bell-crank lever in this case not only takes up considerable construction space but likewise extends upwards in the initial and end positions, so that the overall height and overall length of the housing become undesirably large. Furthermore, the housing is set up for always driving two base sections, so that a solution for one base section is ruled out from the start.
The object of the invention is to provide the adjusting drive both in a more compact manner and with the feature of a single-base drive.
This and other objects are achieved according to the invention in that the electric motor is connected via gearing to a rotatably mounted eccentric in a round disc located in the vertical plane and having an external tooth system. The disc is supported in a fixed position relative to the outer frame, such that the external tooth system meshes with a ring of larger internal circumference and having an internal tooth system. The rod for transmitting the adjusting force to a base section is fastened to the ring. As a result, the adjusting drive not only becomes compact, but the feature of using the adjusting drive separately for only one of the base sections is also obtained. The greater compactness is obtained from the resulting flat disc design. The force transmission also takes place only in the lifting direction of the base section. A plurality of such small adjusting drives may be used for base sections of different widths.
In a further embodiment of the invention, provision is made for the electric motor, lying parallel to the outer frame, to be connected to the eccentric via an angular drive. As a result, space is likewise saved and the compactness is increased.
Furthermore, the fact that the angular drive consists of reduction gearing constitutes an improvement. As a result, the requisite speed reduction of the motor can partly take place in the first stage.
The fact that the reduction gearing includes standard worm gearing provides for an economical selection of the components for the first stage of the drive.
Another economical design of the first stage of the drive also results from the fact that the electric motor is designed like a windshield wiper motor from motor vehicles.
In addition, the fact that the electric motor with angular drive is fastened directly to the base plate of the ring having an internal tooth system saves additional construction space.
In yet a further embodiment of the invention, the fixed support for transmitting the torque is designed such that the disc is held on the outer frame in a flexible manner relative to the latter by means of a bar-shaped torque support.
The flexibility may now be configured in such a way that the torque support at the fastening point on the outer frame has an elongated hole for the fastening element or comes to bear on one side. The round disc with the external tooth system on which the torque support is screwed in place, can transmit the eccentric movement to the torque support, which is free to absorb the eccentric movement.
Furthermore, it is advantageous that the eccentric in the round disc is rotatably mounted by means of a rolling or sliding bearing. As a result, the eccentric movement can be transmitted without a large amount of resistance.
The speed to be transmitted by the electric motor to the respective base section, which speed requires considerable deceleration, is provided by virtue of the fact that a reduction ratio is formed from the speed reduction of electric motor/worm gearing and external tooth system/internal tooth system. The internal tooth system having the larger diameter for receiving the external tooth system, which has a smaller diameter.
An optimum adaptation of the speed reduction is obtained from the relationship to the effect that the number of teeth of the worm gearing is Z1=60, that of the internal tooth system is Z2=120 and that of the external tooth system is Z3=118 and the overall reduction ratio is i=3600:1.
The range of use of the invention is clearly shown by the fact that the drive, consisting of electric motor and reduction gearing, is assigned as a unit in each case to one or two base sections. As a result, one or more base sections may be equipped with single or twin drives.
The arrangement may also be varied by virtue of the fact that, for a narrow seat or a narrow couch, the drives are fastened in mirror image fashion in each case to the inside of the outer frame.
A further possible variation is obtained by the fact that, for a wide seat or a wide couch, pairs of drives are fastened in mirror image fashion to the two insides of the outer frame.
The various features of novelty which characterize the invention are pointed out with particularly in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.